This application claims the benefit of Korean Application No. 2002-1694, filed Jan. 11, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a developing system of a liquid electrophotographic image forming device, and more particularly, to a developing system capable of regulating a developer layer on a development roller of a liquid electrophotographic image forming device using a high-concentration liquid developer.
2. Description of the Related Art
In general, developing systems of liquid electrophotographic image forming devices form an electrostatic latent image corresponding to a desired image by scanning light on a photosensitive body, develop the electrostatic latent image using a developer in which powder-shaped toner is mixed with a liquid solvent, and print the developed electrostatic latent image on a paper.
FIG. 1 is an example of a conventional developing system of a liquid electrophotographic image forming device. Referring to FIG. 1, the conventional developing system of a liquid electrophotographic image forming device includes a photosensitive body 10 which is supported by a plurality of rollers 11 and moves as an endless track, a developing unit 20 to develop an electrostatic latent image formed on the photosensitive body 10, and a transfer unit 30 to transfer the electrostatic latent image onto a paper P.
The photosensitive body 10 is charged to a predetermined electric potential by a charger 12, and the charged electric potential varies depending on light beams scanned by a laser scanning unit (LSU) 13 installed adjacent to the photosensitive body 10 such that the electrostatic latent image is formed. Next, the electrostatic latent image formed on the photosensitive body 10 is developed by the developing unit 20, and the developed image is transferred onto a transfer roller 14 and is printed onto the paper P passing through the transfer roller 14 and a fusing roller 15.
The structure of the developing unit 20 is shown in FIG. 2. Referring to FIG. 2, the developing unit 20 develops the electrostatic latent image formed on the photosensitive body 10 using a developer to form an image. The developing unit 20 includes a development roller 23 that is installed to be rotatable in a main body 21, a manifold 22 to spray the developer between the development roller 23 and the photosensitive body 10, and a squeeze roller 24. Reference numerals 25, 26, and 27 denote a cleaning roller to clean the surface of the development roller 23, a development backup roller, and a squeeze backup roller, respectively.
In the structure of FIG. 2, the electrostatic latent image formed on the photosensitive body 10 is developed using a liquid developer that is sprayed between the development roller 23 and the photosensitive body 10 by the manifold 22, and a liquid carrier left on the photosensitive body 10 is removed with the squeeze roller 24.
A low-concentration liquid developer (less than 2.5-3% solid) is used in the developing system of a liquid electrophotographic image forming device, thereby obtaining a high quality image. However, since the concentration of the developer in an ink cartridge (not shown) to supply the developer to the developing system is 25% solid, a complicated developer supplying unit is required to change the high-concentration developer to the low-concentration developer. Thus, the size of the image forming device increases, and the image forming device has a complicated structure. Also, after development of the image, a system to control the concentration of the liquid developer depending on variations in the toner particles is required when the developer is refilled.
Thus, in order to solve these problems, a new developing system using a high-concentration developer greater than 3% solid is required. A developer layer on the development roller should be regulated regardless of the concentration of the developer.
Accordingly, it is an object of the present invention to provide a developing system for a high-concentration liquid electrophotographic image forming device, which is capable of improving the quality of an image by regulating a developer layer on a development roller.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing a developing system of a liquid electrophotographic image forming device. The developing system includes a development container in which a developer is stored; a photosensitive body; a development roller to rotate opposite to the photosensitive body, the development roller being partially soaked in the developer in development container; and a metering blade to maintain a layer of the developer on the development roller at a constant thickness, the metering blade including a first face contacting the development roller, and a second face forming an angle with respect to the first face, wherein a point at which the development roller contacts the first face of the metering blade is spaced from an edge at which the first and second faces intersect.
According to an aspect of the present invention, the metering blade is an L-shaped metal plate.
According to another aspect of the present invention, the point at which the circumference of the development roller contacts the first face of the metering blade is spaced more than 1 mm apart from the edge, and a force per centimeter applied to the circumference of the development roller by the metering blade is about 100-200 gf/cm.
According to still another aspect of the present invention, surface roughness of the metering blade is less than 0.5 xcexcm, and an angle between the first face and the second face of the metering blade is about 90 degrees.